R1211x Series PWM Step-Up DC/DC Controller NO.EA-088-160113 OUTLINE The R1211x is a CMOS-based PWM step-up DC/DC converter controller with low supply current. The R1211x consists of an oscillator, a PWM control circuit, a reference voltage unit, an error amplifier, a reference current unit, a protection circuit, and an under voltage lockout (UVLO) circuit. A low ripple and high efficiency step-up DC/DC converter can be configured by only adding few external components, such as an inductor, a diode, a power MOSFET, divider resisters, and capacitors. The R1211x002B/D has a bu-in ilt phase compensation, while the R1211x002A/C can set a phase compensation externally. The R1211x002B/D has standb-y mode. The max duty cycle is internally fixed at 90% typically. A soft-start function is built-in, and a soft-starting time is set at 9 ms typically (R1211x002A/B, 700 kHz) or 10.5 ms typically (R1211xC/D, 300 kHz). The R1211x has a latch-type protection circuit, which latches the external driver in off-state if the maximum duty cycle continues for a specified time after soft-starting time. The protection delay time can be set with an external capacitor. To release the protection, turn the power off and back on (power source voltage lower than UVLO detector threshold) or make the device into standby mode and back to active mode using the CE pin. FEATURES Input Voltage Range ............................................ 2.5 V to 6.0 V Oscillator Frequency (PWM Control) ................... 300 kHz, 700 kHz Maximum Duty Cycle ........................................... Typ. 90% Standby Current .................................................. Typ. 0 A (R1211x002B/D) Feedback Voltage ................................................ 1.0 V Feedback Voltage Accuracy ................................ 1.5% UVLO Threshold Level ........................................ Typ. 2.2 V (Hysteresis Typ. 0.13 V) Feedback Voltage Temperature Coefficient......... 150 ppm/C Built-in Latch-type Protection Circuit ................... Protection delay time can be set with an external capacitor Packages ............................................................. SON-6, SOT-23-6W APPLICATIONS Constant Voltage Power Source for Portable Equipment Constant Voltage Power Source for LCD and CCD 1 R1211x NO.EA-088-160113 BLOCK DIAGRAMS R1211x002A/C Block Diagram R1211x002B/D Block Diagram SELECTION GUIDE In the R1211x, the oscillator frequency, the optional function, and the package type are user -selectable options. Selection Guide Product Name Package Quantity per Reel Pb Free Halogen Free R1211D002x-TR-FE SON-6 3,000 pcs Yes Yes R1211N002x-TR-FE SOT-23-6W 3,000 pcs Yes Yes x: Designation of Oscillator Frequency and Optional Function (A) 700 kHz, with AMPOUT pin (External Phase Compensation Type) (B) 700 kHz, with CE pin (Internal Phase Compensation Type, with Standby) (C) 300 kHz, with AMPOUT pin (External Phase Compensation Type) (D) 300 kHz, with CE pin (Internal Phase Compensation Type, with Standby) 2